TRIP (Transformation Induced Plasticity) and DP (Dual-Phase) steels are written in a new series of steels which present excellent mechanical properties. As for microstructure aspect, TRIP steels consist on a ferrite matrix with a second phase dispersion of other constituents, such as bainite, martensite and retained austenite, while dual-phase steels consist on martensite dispersion in a ferrite matrix. In order to identify the different microconstituents present in these materials, microstructure characterization techniques by optical microscopy (using different etchants: LePera, Heat-Tinting and Nital) and scanning electron microscopy were carried out. This being so, microstructures were correlated with mechanical properties of materials, determined by means of tensile tests. It is concluded that steels assisted by TRIP effect have a strength and elongation relation higher than the dual-phase one. With microstructure characterization, it was observed phases present in these materials microstructure.
The performance of multiphase steels is closely related to their microconstituents. Thus, the characterization and effective control of the microstructure of these materials are crucial, and chemical attack processes are essential for this to occur. In this context, this study sought to employ the Taguchi method to evaluate the chemical etching process with the LePera reagent in order to investigate the influence of different process variables, in addition to the interactions between them, on the quality of the image obtained. The variables analyzed were: concentration of picral (CP) and sodium metabisulfite (CSM) solution, pre-attack (PA), drying mode (DM) and attack time (AT). in addition to the relative humidity and temperature of the environment. Therefore, a quality index (QI) was suggested for the images obtained, which, together with the analysis of variance, indicates the best route for microstructural characterization of TRIP800 steel (CP-4.0%; CSM-0.5% ; PA-No; DM-Natural; AT-25s; . Temperature (°C): 15I---25 and Relative humidity (%): 55I---90). In addition to indicating the variables that most influence the process. The influence of noise factors (temperature and relative humidity) was also proven.
In the second half of the last century, the automobile industries were affected from the petroleum crisis caused mainly by the wars in the Middle East. These crises led the automakers reconsider their vehicles. One of the most important events after that was the adoption of new steels by the industry. One example is the TRIP steels (Transformation-induced plasticity). In this work, a specimen of TRIP steels was etched using LePera reagent. The obtained images were analyzed using digital processing. Using the ImageJ software the methods threshold and watershed were studied. The methods were compared: the morphological characteristics and volumetric fraction of the retained austenite and martensite phases were analyzed. The results showed that the threshold led to a higher number of identified grains with lower mean area and total area fraction than the watershed method.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.